A lateral well bore is drilled off a primary well bore at a position along its length. The lateral well bore is drilled through the casing or through a preformed window in the casing of the primary well bore. Completion of these lateral well bores often involves introduction of a liner thereto.
The liner is inserted through the window in the casing and into the lateral well bore. According to one method, the liner is then cemented in place and any end protruding into the primary well bore is milled off. According to another method, the liner is hung off the primary well bore casing by a tieback hanger. The tieback hanger is formed as an open ended tube. The first end of the tube conforms to the shape of the window and is often inclined relative to the long axis of the tube. The opposite end of the tube is connected to the lateral liner. At the first end, the tieback hanger has formed thereon a flange, or other engagement means, for catching on the edges of the casing.
When the liner is in place in the lateral well bore and run in pressure is released, the liner tends to recoil back towards the primary well bore. Sometimes recoiling causes the liner and the attached tieback hanger, if any, to be displaced back into the primary well bore. The liner or tieback hanger then becomes an obstruction to the passage of downhole tools through the primary well bore past the lateral well bore.